Gravitational lens reveals details of distant, ancient galaxy

Mar 08, 2012

This graphic shows a reconstruction (at lower left) of the brightest galaxy, whose image has been distorted by the gravity of a distant galaxy cluster. The small rectangle in the center shows the location of the background galaxy on the sky if the intervening galaxy cluster were not there. The rounded outlines show distinct, distorted images of the background galaxy resulting from lensing by the mass in the cluster. The image at lower left is a reconstruction of what the lensed galaxy would look like in the absence of the cluster, based on a model of the cluster's mass distribution derived from studying the distorted galaxy images. Credit: Courtesy of NASA; ESA; J. Rigby (NASA Goddard Space Flight Center); K. Sharon (Kavli Institute for Cosmological Physics); and and M. Gladders and E. Wuyts (University of Chicago)

Thanks to the presence of a natural "zoom lens" in space, University of Chicago scientists working with NASA's Hubble Space Telescope have obtained a uniquely close-up look at the brightest gravitationally magnified galaxy yet discovered.

In this case, gravity from the galaxy cluster RCS2 032727-132623 bent and amplified the light coming from a much more distant galaxy, 10 billion light-years from Earth. This "gravitational telescope" creates a vast arc of light, as if the distant galaxy had been reflected in a funhouse mirror. The UChicago team reconstructed what the distant galaxy really looks like, using computational tools that reversed the effect of gravitational lensing.

"What's happening here is a manifestation of general relativity," said Michael Gladders, assistant professor in astronomy & astrophysics at UChicago. "Instead of seeing the normal, faint image of that distant source, you see highly distorted, highly magnified, and in this case, multiple images of the source caused by the intervening gravitational mass."

The cosmic lens gave the UChicago team the unusual opportunity to see what a galaxy looked like 10 billion years ago. The reconstructed image of the galaxy revealed regions of star formation glowing like bright points of light. These are much brighter than any star-formation region in Earth's home galaxy, the Milky Way.

'Looking at the nature of dark matter'

In 2006 the Chicago astronomers used the Very Large Telescope in Chile to measure the arc's distance and calculated that the galaxy appears more than three times brighter than previously discovered lensed galaxies. Then last year, Jane Rigby of NASA's Goddard Space Flight Center in Greenbelt, Md., and the Chicago team imaged the arc with the Hubble Space Telescope's Wide Field Camera 3.

Using this gravitational lens as a telescope offers two major scientific opportunities, Gladders said. First, "It gives us a look at that very distant source with a precision and fidelity that we couldn't otherwise achieve," he said.

And second, it provides an opportunity to learn something about the lens-forming mass, which is dominated by dark matter. "It's really a way of looking at the nature of dark matter," Gladders said. Dark matter accounts for nearly 90 percent of all matter in the universe, yet its identity remains one of the biggest mysteries of modern science.

Keren Sharon, a postdoctoral scholar at UChicago's Kavli Institute for Cosmological Physics, led the effort to perform a detailed reconstruction of the lensed galaxy. She and her co-authors, including Gladders, NASA's Rigby and UChicago graduate student Eva Wuyts, published their findings this month in the Astrophysical Journal.

Sharon painstakingly created a computer reconstruction of the gravitational lens, then reverse-engineered the distorted image to determine the distant galaxy's actual appearance. "It's a little bit of an art, but there's a lot of physics in it. That's the beauty of it," Sharon said. "It was a fun puzzle to solve, especially when we had such great data."

Gladders said Sharon is "one of the world experts on exactly how to do this. Combine that degree of finesse with this quality of data, and you get a very nice result. This object now becomes not only the brightest-lensed source known, but because of this analysis, it is also going to be one of the best-understood sources."

Through spectroscopy, the spreading out of light into its constituent colors, the team plans to analyze the distant galaxy's star-forming regions from the inside out to better understand why they are forming so many stars.

The team also has obtained data from one of the twin Magellan Telescopes to help them determine why the galaxy, which is 10 billion light years away, looks so irregular.

"It's not like we have something to compare it to," Sharon said. "We don't know what other galaxies at the same distance look like at this level of detail."

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Given the need for dark matter to make the mathematics work for this inference, as seems to be the case for most of these lensing inferences, how much certainty should we really afford this hypothesis? Isn't the dark matter simply proposed because the math doesn't work to form the lens without it? How scientific is that really? Where I come from, this is called a mathematical fudge factor.

You know, if astrophysicists refuse to consider competing explanations, the public will just build a social network to do the work without them. And the institution of establishment science can in this manner come to be viewed as little more than a single line of investigation.

As far as i know astrophysists do consider 'competing' theorys. I wouldve thought the scientific community works in a way that research is generally conducted with currently accepted theory as a framework because its... currently accepted theory. At the same time there will be scientists working on projects hypothesising other frameworks that appear to 'go against' currently accepted theory. But seeing as being 'against' something is a completely socialogical behaviour it doesnt really mean anything in scientific circumstance. Yes, theorys do compete, on the amount of testable evidence that supports a claim, vice versa.Its not that anyone refuses to consider other explanations, im sure other postulations are made all the time, thats pretty much their job But currently accepted theory is best fit weve got at the moment.

Yes it might 'change direction' in the future enough supporting evidence for another model, or more likely an adjustment to the model, may sway enough of the scientific community to consider it the currently accepted theory.sorry to go on, but I often read posts because i enjoy reading others' opinions and postulations, but some of you just seem angry, thinking the scientific community is some all powerful propaganda machine, just because the media clearly sensationalisesscienctific research and hollywood and religion demonise it. And the energy/industrial complex, i dont even wanna go there.

Re: "But seeing as being 'against' something is a completely socialogical behaviour it doesnt really mean anything in scientific circumstance."

I am perpetually amused at this notion that scientists are somehow not bound by the findings of sociology. When sociologists tell us that people tend to exhibit all of the traits of "motivated reasoning," whereby we on average tend to specifically seek out that evidence which supports our pre-existing views, I fail to observe any footnotes which exclude scientists from this very human behavior. The scientific method is just a collection of people trying their hardest to think like scientists. Whether or not they are actually successful depends entirely upon how much they understand themselves, their institution of science and the influence of others upon their own thoughts. It is common knowledge that PhD students that exhibit divergent views are purged from the programs. See Jeff Schmidt's Disciplined Minds & physorg sociology articles.

The dirty secret for those who are so eager to focus on the dominant theories, to the complete exclusion of others which can be made to work, is that they effectively undermine their own ideational fluency. Creativity researchers are quite clear on the ramifications of this: Creative problem-solving absolutely depends upon the quantity of ideas which a person is familiar with. Thus, for those who keep on following the completely passive suggestion that "extraordinary claims demand extraordinary evidence" (the Sagan Standard), they will never come close to truth. That's because the truth does not arrive on one's doorstep, all dressed up in beautiful equations from the stork. The truth is spread out in a million partial, incomplete solutions which we are tasked with synthesizing together. The widespread adoption of the Sagan Standard has stalled scientific discovery, for it implies an extremely passive process which does not come close to dealing with the information deluge we see.

It is easy to not see that we have a major problem in the sciences -- especially physics -- until one learns of the results of "force concept inventory" tests. These tests don't judge a person's ability to memorize problem-solving routines. They evaluate a person's CONCEPTUAL COMPREHENSION. Even students in classes at Harvard can easily be demonstrated to exhibit dismal scores on these tests.

So, the real problem here is this: If students don't understand the concepts of physics sufficient to explain them, then how in the world can they compare and contrast scientific frameworks? The straightforward answer is that very, very few can. We are training an army of specialists who are completely incapable of questioning the assumptions we force them to memorize.

And the vital implication is that where you see such problems in our educational system, there will be inevitable consequences for scientific theory.

if astrophysicists refuse to consider competing explanations, the public will just build a social network to do the work without them

We should simply stop to pay these parasites - it would be a much more effective. After all, the lost of fifty years of contemporary cosmology is far not so expensive for human civilization as the lost of one month in cold fusion research. We have no usage for contemporary astronomy and what's worse: without implementation of cold fusion we will never have.

Hopefully, I don't need to actually explain that you should expect more of yourself in seeking out competing views. It should be painfully obvious that reading selection can entirely determine belief. Here is a "prettier" link, making a similar case ...

What is so heretical about Arp's views of quasars, aside from the fact that his findings basically disprove the Big Bang Theory? Without a doubt, his work is no less speculative than the proposition that the universe's observable matter represents just 5% of the total.

By spending so much effort defending the conventional theory from Arp, conventional thinkers never develop the fluency required to formulate a meaningful opinion on Arp.

You are claiming others refuse to look at alternative answers yet you are pushing a theory that has the Sun powered by electrical currents flowing into it from outside. Which must be invisible since no one has detected them and you don't even have a reason for it not being detected.

On top of which your own theory only produces, AT BEST, 25% of the Suns actual energy production. Which would still be a detectable current flow.

Then there is ludicrous claim that Supernova are caused by an Electro Blasto with enough energy to sunder a 100 solar mass star and drive the debris to 10% of light speed.

Of course at no point on any of the sites you push does anyone have any explanation of the source for that energy. It is just a magical current powered by ... well by nothing except itself.

You perfectly exemplify my point, as you lack the ideational fluency required to understand that the EU theorists propose a drift current for the incoming electrons, within the domain of the heliosphere. The electrical currents are not visible until one looks beyond the heliopause, where Gerrit Verschuur very clearly describes as highly filamentary. Drift currents are such a fundamental concept that it should in fact be the first inference (it is for electrical currents traveling through wires!).

This approach you've chosen here does not involve critical thinking. Critical thinking is a process of questioning assumptions. Nobody will ever succeed at forcing you to think critically about the concepts you have memorized. This is a completely personal experience which absolutely validates the notion that one cannot understand the universe before they first understand themselves.

The rest of your post is so off the mark that it doesn't demand a response. I'm sorry.

By the way, if you were to look up the operation of a plasma glow discharge in the engineering book, Gaseous Conductors by Cobine, you would observe that engineers know that within the plasma cell of the discharge, the incoming current is a DRIFT current.

All that Wal Thornhill has done, which elicits so much ire from conventional thinkers, is to propose that the Sun is basically a plasma glow discharge just like an HID light. We can study these things in the laboratory. People do. And every single feature you see on the Sun can be correlated with our observations of laboratory plasma glow discharges.

Conventional astrophysicists simply refuse to do so. They will waste our time with their thought experiments for as long as the public permits them to. Meanwhile, our economy will continue to stagnate. Do you realize that per-capita innovation has been on the decline since the turn of the 20th century?

And what does that have to do with it not being detected despite the amount of power that would needed?

thinkers, is to propose that the Sun is basically a plasma glow discharge just like an HID light.

What is the power source?

Of course it is glowing plasma. What makes it glow? What drives the current? HID lights are powered by the whatever is driving the generators AND they produce almost all the energy in the UV bands yet the surface of the Sun exhibits a black body radiation curve completely unlike HID lights.>>

Wow, interstellar clouds ARE INDEED visible by virtue of their radio emissions. One need only observe them on the 21-cm wavelength - the same exact signal which radio astronomers use to look for alien intelligence.

Btw, I am definitely NOT who you think I am.

Also, this constant insistence on explaining the source of the universe's power is not even a scientific question. It is just as metaphysical as demanding an explanation for the origin of the Big Bang.

As for the detectability of drift currents, it would require a space mission whose intended purpose is to measure such a current. The problem is that electrons in a drift current move in all sorts of directions. It is their *NET* flow which causes an electrical current. If you slow down and just think about this problem for a moment, it will become apparent how difficult this would be to measure. One would have to compare relative densities of charge at different points of the heliosphere, to show it increases near the Sun.

You know, Ethelred, the EU theorists are very nice people. They actually respond to friendly questions by email regularly. You could have decided to vet your questions with the actual scientists themselves. But, you seem very determined to validate your pre-existing beliefs, and you don't demonstrate any concern for the errors that I'm pointing out in your interpretation of *their* theory. As an approach to controversy, you will always end up at conventional wisdom in this manner. Science is not like sports: In sports, we root for our favorite teams. But, in science, truth matters more than all else. And our own personal psychology stands in the way of tracking it down. This is not to single YOU out. It is a challenge which every single one of us faces every day.

The Sun's power source is the arms of the Milky Way galaxy. But, don't expect me to try to explain this to you. A person cannot possibly learn when they argue with everything that somebody says. We know that the filaments which connect the stars are in fact electrical because we can see many of them emitting critical ionization velocities, which is the hallmark signature of charged particles slamming into neutral clouds of gas. In fact, there are some filaments -- the high-velocity clouds -- which remain anomalous to the mainstream because astrophysicists refuse to acknowledge that the 35 km/s redshift associated with them is in fact a CIV.

Per-capita innovation is indeed on the decline, and you should care enough to actually look it up.

Wow, interstellar clouds ARE INDEED visible by virtue of their radio emissions

WOW how is that answering my question of where the SUN is getting its power?

Btw, I am definitely NOT who you think I am.

Perhaps but that is the first time you have said so. You have always ignored my mentioning YEP in the past.

Also, this constant insistence on explaining the source of the universe's power is not even a scientific question.

That is two silly statements. I didn't ask for the source of the power of the Universe. I asked for the source of the SUN'S power. And it is VERY scientific to ask that. IT MUST HAVE A SOURCE of energy. What is that source? In YOUR theory it is electric current but THOSE MUST HAVE A SOURCE OF POWER. What is that source?

In standard theory the source of the Sun's power is hydrogen fusion. The conversion of matter to energy. Stuff we KNOW occurs as we have done here on Earth via both fission and fusion.>>

If you slow down and just think about this problem for a moment, it will become apparent how difficult this would be to measure.

If you quit evading you will notice that the AMOUNT of power needed to match the Sun's output would require a DETECTABLE flow into the Sun.

One would have to compare relative densities of charge at different points of the heliosphere, to show it increases near the Sun.

No. One would have to show that there is a flow from outside the Sun towards the Sun since the claim on the Electro Blasto sites is that the Sun is powered by an OUTSIDE current. If you are claiming the current is generated wholly with the Sun and and its corona THEN:

You are not using the Electro Blasto Theory and thus you still need a source of power for the currents.

We know that the filaments which connect the stars are in fact electrical because we can see many of them emitting critical ionization velocities,

Where are those IN OUR SOLAR SYSTEM?

which is the hallmark signature of charged particles slamming into neutral clouds of gas.

Which is not occurring in our SOLAR SYSTEM.

You are doing a lot of work to avoid answering a question you should be able to answer if you know what you are talking about. I have read those sites. I am NOT going on any rote memorization. YOU are doing that. I understand what I am saying and asking.>>

I also understand that you have been trying give the appearance of responding while not actually responding. You have to do that sort thing intentionally. Perhaps you need to look into YOUR personal motivations instead attacking me. You might also note that I have lot of experience in dealing with evasive people on forums. I am not going to be derailed by your personal attacks.

Per-capita innovation is indeed on the decline, and you should care enough to actually look it up.

You should care enough to provide a source. You made the claim. Back it up.

WHAT IS POWERING THE SUN? You seem to think you have the answers.

It is time to stop evading questions and engaging in personal attacks and just answer the question or admit you don't have the answers you are pretending you do.

Given the need for dark matter to make the mathematics work for this inference, ... this is called a mathematical fudge factor.

Dark Matter is indeed a "fudge factor". That's why the called it "Dark" matter. Nobody denies that it is invoked to explain observations which are beyond our current understanding as per our theories. If you look around, there are quite a handful of dark matter models and stand-ins. They are all working towards the goal of trying to make sense of what is observed. All these models place limits on measurable terms (beyond which the model deviates drastically from observations). As long as observations do not show these limits as broken, any model is as good as the other. And that's another problem - there can't surely be so many models for one phenomenon. So the observations get better, which get rid of some models and so on. The term "Dark Matter" is generic. It does not mean a particular model.

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